Perhaps you should try some spelling variations:
sach tranh » canh tranh
nghiem dau » nghiep dau, nghiem ban, nghiem ma
nghiem lam » nghe lam, nghiem ban, nghiem ma
cach trac » cach thuc, anh trac, cach ta
nghiem va » nghiep va, nghiep vua, nghiep vu
te sach » toc sach
tu cach » tu cac
va hoc » van hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach tranh ((nghiem dau) OR (nghiem lam)) hoc ) or ( tu cach trac nghiem va hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tranh ((nghiem dau) OR (nghiem lam)) hoc ) OR ( tu cach trac nghiem va hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach tranh ((nghiem dau) OR (nghiem lam)) hoc ) or ( tu cach trac nghiem va hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach tranh ((nghiem dau) OR (nghiem lam)) hoc ) or ( tu cach trac nghiem va hoc ))*.